This section provides background information related to the present disclosure which is not necessarily prior art.
Dynamoelectric machines such as electric motors and generators convert electric energy into mechanical energy, or vice versa.
Electric motors can be classified into two types: single-phase motors and polyphase motors. Single phase motors are driven by a single phase AC power source, whereas polyphase motors are driven by a polyphase AC power source, which is typically a three-phase AC power source. For purposes of this disclosure, a motor driven by a single phase AC power source is a single-phase motor, even if the motor includes multiple windings such as a main winding and an auxiliary/start winding. In some applications, three phase electric power is highly desirable for use with electric motors because it allows the motor to be more compact, less costly, more efficient, and have less vibration than similar horse power single phase motors.
One advantage of balanced three phase power is that it does not require a neutral wire. Thus, all three conducting wires may be coupled together to form a neutral connection. In many three phase electric motors, the neutral connection is created by connecting a neutral wire from each phase winding together at a single point. For motors with many phase windings (e.g. 6, 9, or 12 windings) or large diameter conducting wires, this connection may be bulky or hard to manufacture. This is because the connecting requires grouping many wires together and then connecting them. Furthermore, connecting a mass of wires of this size, in many instances, requires welding or melting which may be time consuming and expensive.